Nicholas Carr's blog

Category Archives: The Shallows

A now famous Stanford study by Eyal Ophir and Cliff Nass (et al.) found that heavy media multitaskers — people who constantly shift their attention between different of streams of information — have less control over their thoughts and less ability to distinguish important information from unimportant stuff. In a word, heavy multitaskers are scatterbrained. A new study, “Higher Media Multi-Tasking Activity Is Associated with Smaller Gray-Matter Density in the Anterior Cingulate Cortex,” by two neuroscientists at the University of Sussex’s Sackler Centre for Consciousness Science, may shed light on the biological underpinnings of this mental maladroitness. The researchers, Kep Kee Loh and Ryota Kanai, found that heavy multitaskers have a compromised anterior cingular cortex (ACC), a part of the brain (highlighted in the above images) that plays an important role in the control of thoughts and emotions.

Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today’s society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multitasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM) analyses: Individuals with higher Media Multitasking Index (MMI) scores had smaller gray matter density in the anterior cingulate cortex (ACC). Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences.

Figuring out the “direction of causality” would reveal whether heavy multitasking shrinks the ACC or whether people with less developed ACCs are prone to heavy multitasking. Comments Kep Kee Loh: “The exact mechanisms of these changes are still unclear. Although it is conceivable that individuals with small ACC are more susceptible to multitasking situations due to weaker ability in cognitive control or socio-emotional regulation, it is equally plausible that higher levels of exposure to multitasking situations leads to structural changes in the ACC. A longitudinal study is required to unambiguously determine the direction of causation.”